Engineering pseudo-spin and valley degrees of freedom using quantum spin Hall and valley Hall effects opens up remarkable possibilities for highly efficient and robust signal transport in time-reversal invariant photonic systems. Here, we present a spin-valley locked photonic crystal that has distinct signs of chirality of sublattices in a honeycomb unit cell. We show that the photonic crystal has an insulating bulk dispersion and sublattice-dependent spin-valley coupled gapless edge states by exploiting a coupled dipole method and demonstrate valley-selective propagation by controlling spin state of an external dipole source. The interplay between spin, valley and sublattice shows a judicious way for one-way photon transport by using multiple degrees of freedom.

中文翻译：

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交错手性光子晶体中的自旋谷锁定拓扑边缘状态

使用量子自旋霍尔效应和谷霍尔效应设计伪自旋和谷自由度为时间反转不变光子系统中高效和稳健的信号传输开辟了非凡的可能性。在这里，我们提出了一种自旋谷锁定光子晶体，它在蜂窝晶胞中具有明显的亚晶格手性迹象。我们通过利用耦合偶极子方法表明光子晶体具有绝缘体色散和依赖于亚晶格的自旋谷耦合无间隙边缘状态，并通过控制外部偶极子源的自旋状态证明了谷选择性传播。自旋、谷和亚晶格之间的相互作用通过使用多个自由度显示了一种单向光子传输的明智方式。